The Kru (cell of sacred amulets) discovered at Wat Chanasongkram was originally created by HRH Prince Maha Surasee, (The Tiger General), royal brother of King Rama I the Great during the first period of the Chakri dynasty.
These amulets were created around 200 years ago and retained in a Kru located inside a chedi. They were re-discovered in B.E.2495, when the Abbot, Jaokun Pradharmpitok relocated the chedi to make room for a new school.
The Abbot decided to give these amulets away to all the donors who had supported the construction of the new school and other renovation projects within the temple.
Originally these amulets were quite fragile and were easily broken, as they were made from unbaked soil and Bailarn leaves. Jaokun Pradharmpitok decided to preserve the amulets by baking them.
Pims
There were many different Pims (styles) found in the Kru including Pim Prokbhoti, Pim Soomtaowanlui, Pim Kang Yun, Pim Pidta, etc.
It was said that a policeman who was shot was wearing one of these amulets miraculously escaped un-injured. As a result, the fame of these amulets increased substantially.